This invention relates to polymer latices containing magnetically-charged material and to processes for preparing polymer latices containing magnetically-charged material.
Magnetic polymers in the form of gels or particles are generally obtained by mixing a magnetically-charged material into a polymer prepared by conventional bulk, solution, emulsion or suspension polymerization methods. In the preparation of magnetic polymers, however, an additional stage, such as atomization, coagulation, extrusion and distillation of the solvent is often required, thus necessitating both suitable equipment and the expenditure of more than trivial energy. Further, in preparing magnetic polymers, workers often encounter dispersion difficulties, resulting in polymer particles having both defective magnetic charge distributions and modified properties.
Although mixing a magnetically-charged material into a polymer latex is also known, special polymers have heretofore been required to disperse the magnetic charge. The products obtained, moreover, often lack adequate stability.
To overcome these problems, workers have suggested addition of a magnetically-charged material during the emulsion polymerization of a mixture of monomers, at least one of which is water-soluble. Disadvantageously, however, hydrophilic polymers of restricted applicability are formed.
Moreover, addition of a magnetically-charged material during the emulsion polymerization of water-insoluble monomers produces unsatisfactory results because the magnetically-charged material fails to be incorporated into the polymer particles during polymerization.